CVE-2025-48047: NetFax Server RCE Vulnerability

CVE-2025-48047 Overview

CVE-2025-48047 is a critical command injection vulnerability affecting MICI NetFax Server. An authenticated user can perform command injection via unsanitized input to the NetFax Server's ping functionality via the /test.php endpoint. This vulnerability allows attackers with valid credentials to execute arbitrary system commands on the underlying server, potentially leading to complete system compromise.

Critical Impact

Authenticated attackers can achieve full system compromise through command injection, enabling data exfiltration, lateral movement, and persistent access to affected systems.

Affected Products

• MICI NetFax Server

Discovery Timeline

• May 29, 2025 - CVE-2025-48047 published to NVD
• May 29, 2025 - Last updated in NVD database

Technical Details for CVE-2025-48047

Vulnerability Analysis

This vulnerability is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), commonly known as OS Command Injection. The /test.php endpoint in MICI NetFax Server provides ping functionality that fails to properly sanitize user-supplied input before passing it to system shell commands.

When an authenticated user submits a request to the /test.php endpoint, the application takes user input intended for a ping target and passes it directly to the operating system command interpreter. The lack of input validation allows attackers to inject shell metacharacters and additional commands that execute with the privileges of the web application process.

The network-accessible nature of this vulnerability combined with the high privileges typically associated with server-side command execution creates a significant risk for complete system compromise. Successful exploitation can lead to unauthorized access to sensitive data, modification of system configurations, and potential lateral movement within the network.

Root Cause

The root cause of CVE-2025-48047 lies in the failure to implement proper input sanitization and validation in the /test.php endpoint. The application directly incorporates user-controlled input into shell commands without escaping or filtering dangerous characters such as semicolons (;), pipes (|), ampersands (&), backticks (`), or command substitution sequences ($()). This allows attackers to break out of the intended ping command context and execute arbitrary system commands.

Attack Vector

The attack is conducted over the network against the NetFax Server's web interface. An attacker must first authenticate to the application, making this a post-authentication vulnerability. Once authenticated, the attacker can craft malicious requests to the /test.php endpoint containing shell metacharacters and arbitrary commands appended to or injected within the ping target parameter.

For example, an attacker might submit a request where the target field contains shell command separators followed by malicious commands. The server's failure to sanitize this input results in execution of both the legitimate ping command and the injected malicious commands. According to the Rapid7 Blog on CVE-2025-48045, this vulnerability remains unpatched by the vendor.

Detection Methods for CVE-2025-48047

Indicators of Compromise

• Unusual requests to /test.php endpoint containing shell metacharacters (;, |, &, `, $())
• Unexpected child processes spawned by the web server process
• Suspicious outbound network connections originating from the NetFax Server
• Evidence of unauthorized user creation or privilege escalation on the host system

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing command injection patterns targeting /test.php
• Monitor web server access logs for abnormal request patterns to the test endpoint, particularly those containing encoded or special characters
• Deploy endpoint detection and response (EDR) solutions to identify suspicious process execution chains originating from web server processes
• Configure SIEM alerts for authentication events followed by requests to diagnostic or test endpoints

Monitoring Recommendations

• Enable verbose logging on the NetFax Server application and underlying web server
• Implement network traffic analysis to detect command-and-control (C2) communications that may result from successful exploitation
• Monitor for file system changes in sensitive directories that could indicate post-exploitation activity

How to Mitigate CVE-2025-48047

Immediate Actions Required

• Restrict access to the NetFax Server web interface to trusted IP addresses only
• Disable or remove access to the /test.php endpoint if ping functionality is not required
• Implement additional authentication requirements or access controls for diagnostic functions
• Consider taking the affected system offline until a vendor patch is available

Patch Information

According to the Rapid7 security advisory, no vendor patch is currently available for this vulnerability. Organizations should implement compensating controls and monitor for vendor updates.

Workarounds

• Deploy a reverse proxy or web application firewall in front of the NetFax Server to filter malicious input before it reaches the application
• Use network segmentation to isolate the NetFax Server from critical infrastructure and limit potential lateral movement
• Implement strict allowlisting for input to the /test.php endpoint, permitting only valid IP addresses or hostnames
• Configure the server to run with minimal privileges to reduce the impact of successful command execution

# Example: Apache mod_rewrite rule to block access to test.php
# Add to .htaccess or Apache configuration
<Location "/test.php">
    Require ip 192.168.1.0/24
</Location>